1. Field of the Invention
The present invention relates to a digital/analog broadcast receiver that can selectively receive a digital broadcast and an analog broadcast.
2. Description of the Related Art
Various vehicular television receivers for receiving analog broadcasts have been devised that enable programs currently being viewed to be watched continuously, even when, as the vehicles on which the receivers are mounted move, reception conditions change, and the channels carrying the programs are gradually altered. For example, disclosed in JP-A-2000-138871 is a television receiver that includes a function for either automatically tuning in a broadcasting station or for switching to an affiliated station, thereby making the uninterrupted viewing of a program possible.
It can be said that the present is a transition period during which broadcasting is being shifted from the transmission of analog to digital signals. In the course of this transition period, an interval (henceforth called a simultaneous broadcasting period) is required during which a broadcasting station provides both analog and digital broadcasts. During this simultaneous broadcasting period, programs can be viewed using either analog broadcast receivers or digital broadcast receivers; or combination digital/analog broadcast receivers can be employed that selectively receive either digital broadcasts or analog broadcasts.
For the analog broadcasting, one channel (a physical channel) is provided for one frequency band allocated for each broadcasting station. For the digital broadcasting, however, one channel (a physical channel) and multiple channels (virtual channels) obtained by dividing physical channels are provided for one frequency band allocated for each broadcasting station. Therefore, for digital broadcasting, more programs can be broadcast using a limited frequency band.
The television receiver disclosed in JP-A-2000-138871 stores, in advance, data including the channel numbers of broadcasting stations that broadcast the same program, and employs this data to automatically change channels. However, when this technique is applied for a digital/analog broadcast receiver, since a digital broadcast channel on which an analog broadcast program is available is not set up for simultaneous broadcasting, channel numbers can not be stored in advance, and therefore, the digital broadcasting channel and the analog broadcasting channel on which the same program is provided can not be switched.
For a conventional digital/analog broadcast receiver, by depressing a channel return key provided on a remote controller or on the front panel of the receiver, a current channel can be changed to a preceding channel across which a program was previously received. However, in order to switch between a digital broadcast and an analog broadcast for a predetermined channel, a user must tune in the desired channel by physically entering the channel number.